#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>

int Fib(int n)
{
	int a = 1;
	int b = 1;
	int c = 1;
	while(n>2)
	{
		c = a + b;
		a = b;
		b = c;	
		n--;
	}
	return c;
}

int main()
{
	int n = 0;
	int ret = 0;
	while (scanf("%d", &n) != EOF)
	{
		ret = Fib(n);
		printf("%d\n", ret);
	}
	return 0;
}